106 



THE POPULAR EDUCATOR. 



tion. Fishes occupying 1 the deep stratum of water have no air- 

 bladder such as the well-known fishes the skate, sole, turbot, 

 and eel. 



The circulatory apparatus consists of a heart with a double 

 cavity and blood-vessels. The upper cavity, the auricle, is 

 thin-walled, and receives the blood from the veins. The lower 

 cavity, the ventricle, is thick and fleshy. By contracting upon 

 the blood it drives it to the gills to be aerated, and thence into 

 the large vessel and system. 



Nervous System. The brain of fishes is small, and made up of 

 a single and three pairs of little masses of nervous matter. 

 The single one is named the cerebellum. The anterior masses 

 give origin to the nerves of the sense of smell. The organ of 

 smell is the same as that of air-breathing animals, except that 

 it is in contact with water. 



The middle pair of masses represents the cerebrum of higher 

 animals. The posterior afford origin to the nerves of sight. 

 The shape of the eye varies considerably in different fishes, but 

 in all the transverse diameter is largest. The size is not in 

 proportion with the body of the fish for example, the salmon's 

 eye is smaller than the haddock's. The eye is flattened in front, 

 so that in some fishes it is almost half a sphere. The pupil is 

 large, so as to take in as much light as possible, but generally 

 motionless.* 



The hearing apparatus is enclosed within the head, having no 

 external ear or auditory canal, for collecting and conveying the 

 vibrations by which sound is produced and transmitted. 



The torpedo and electric eel (Gymnotus electricus) possess an 

 electrical apparatus, which they can discharge at will, communi- 

 cating a shock to any animal with which they come in contact. 

 Humboldt tells us that he has seen two horses killed in five 

 minutes when exposed to the attacks of the electric eel. The 

 latter is a native of the warmer parts of South America, Deme- 

 rara, Surinam, etc. The sensation produced by the shock from 

 the electric fish is exactly that caused by accumulated electricity 

 as developed by the ordinary machine. 



The roe or ovary may be single or double. When distended, 

 it occupies a large portion of the abdominal cavity. The milt, 

 or soft roe of male fishes, has a similar position, and equals in 

 bulk the ovary of the females. They are to the unaided eye so 

 like the female, that it is only in the spawning season they can 

 be distinguished. The ovary is nothing more than a mem- 

 branous bag, with its inner lining folded into broad festoons, 

 wherein the eggs are formed and retained until sufficiently ripe 

 for expulsion. In the eel and lamprey the eggs escape by the 

 rupture of the membrane into the cavity of the abdomen, and 

 from which they pass outwards through a small opening close 

 to the anus. 



In the osseous fishes, the eggs first escape into the sac, 

 and pass out by means of a small duct which opens just 

 behind the anus, as in the herring. In the cartilaginous fishes, 

 as in the shark and ray, there is a much higher type of 

 generative function. The eggs are extremely numerous, amount- 

 ing to many thousands. Leuwenhoeck counted no less than 

 9,384,000 in a middling-sized codfish. Even in the common 

 herring 60,000 eggs have been found in a single female. The 

 parent fob usually selects shallow water for the deposition of 

 her eggs ; this done, her maternal duties and anxieties for her 

 offspring terminate. 



CLASSIFICATION. The best classification of fishes is that 

 adopted by Professor Huxley, viz., into six orders : 



1. Dipnoi. An order of fishes which breathe both by lungs 

 and gills. This order contains only the "mudfish," Lepidosiren 

 and Ehinocryptis. 



2. Elasmobranchii. Sharks, rays, and Chimserae belong to 

 this order. 



3. Ganoidei. An order of fishes mostly extinct. It includes 

 the sturgeons and bony pikes. 



4. Teleostei. Fishes with completely ossified skeletons. 



5. Marsipobranchii, which includes the lampreys and hags. 



6. Pharyngobranchii. The order of fishes represented by the 

 amphioxus, in which the perforated pharynx performs the func- 

 tion of gills. 



Before closing the paper, it is well to remark that though 

 fishes may be the lowest type of the vertebrate series of animals, 



* The eel has a transparent horny convex covering at some distance 

 before tbe eye, to defend it from external accident. 



yet they have the ascendancy over their superior kindred in 

 point of antiquity. Geologists tell us that they were the first 

 of the vertebrals that appeared on the earth, and at an epoch 

 g antecedent to the deposits in which the remains of the 

 ligher animals are found ; and that they possessed equally 

 as high an organisation as the highest fishes of the present 

 day. 



LESSONS IN LATIN. XXXVIII. 



DEVIATIONS IN THE THIED CONJUGATION. 



1. Perfect in -si ; Supine in -SUM. 

 a. The stem ends in d or t : for example, claud, mit. 



i. Claudo, claudere, clausi, clausum, I shut. The compounds 

 have cludo, clusi, clusum ; as, include, I shut up. 



ii. Divide, dividere, divisi, divisum, I divide. 



iii. Laedo, laedere, laasi, laesum, I injure. The compounds have 

 lido ; as, illido, illidere, illisi, illisum, I strike against. 



iv. Ludo, ludere, lusi, lusum, I play. 



v. Plaudo, plaudere, plausi, plausum, I clap my hands. So 

 applaudo, I signify approbation by clapping. The other com- 

 pounds have -odi, -osi, -osum; as, explodo, I drive out by clapping 

 hands. 



vi. Eado, radere, rasi, rasum, I graze, shave (E. E. razor). 



vii. Eodo, rodere, rosi, rosum, I gnaw, slander. 



viii. Trudo, trudere, trusi, trusum, I thrust. 



ix. Vado, vadere (no perfect, no supine), I go. Both perfect 

 and supine are in the compounds; as, evado, evadere, evasi, 

 evasum, I go out, get away. 



x. Cedo, cedere, cessi, cessum, I yield. 



xi. Mitto, mittere, misi, missum, I send. 



xii. Quatio, quatere (no perfect), quassum, J shake. The com- 

 pounds have cutio, cussi ; as, decutio, decutere, decussi, decus- 

 sum, I shake down. 



b. The stem ends in , c, or ct. 



xiii. Mergo, mergere, mersi, mersum, I dip. 



xiv. Spargo, spargere, sparsi, sparsum, I scatter, sow. Com- 

 pounds, spergo, spergere, spersi, spersum : for example, con- 

 spergo, I sprinkle. 



xv. Tergo, tergere, tersi, tersum, I wipe. Another form of 

 tergeo, tergere. 



xvi. Figo, figere, fixi (figsi), fixum, I fix, fasten. 



xvii. Flecto, flectere, flexi, flexuin, I bend. 



xviii. Necto, nectere, nexui, nexum, I tie, knit. 



xix. Pecto, pectere, pexi, pexum, J comb. 



xx. Plecto, plectere, plexi (rare), plexum, J weave. Here 

 may be placed, also, these two : 



xxi. Premo, premere, pressi, pressum, J press. Compounds, 

 primo ; as, comprimo, comprimere, compressi, compressum, I 

 press together. 



xxii. Fluo (stem, flu; noun, fluvius, a river), fluere, fluxi 

 (fluxus as an adjective), I flow. 



VOCABULARY. 



EXERCISE 141. LATIN-ENGLISH. 



1. Templum Jani bis post Numse regnum clausum est. 2. Si ridere 

 concessum sit, vituperatur tamen cachinnatio. 3. Si concessSris esse 

 Deum, confitendum tibi est, ejus consilio mundum administrari. 4. In 

 omnium animis Dei notionem impressit Deus ipse. 5. Magna vis est 

 conscientiee, ut qui peccarint, poanam semper ante oculos versari patent. 

 6. Virtutes ita copulatae, connexseque sunt, ut omnes omnium parti- 

 clpes sint. 7. Cassar populo praeter frumenti denos modios ac totidem 

 olei libras, trecenos quoque nummos viritiin divisit. 8. Qui diffldst 

 perpetuitati bonorum suorum, ei timenduin est, ne aliquando, amissia 

 illis, sit miser. 



